Load and liquid level coordinative control system of multiple stages of pulp preheaters in high-pressure acid leaching and feeding process

Abstract

Provided is a load and liquid level coordinative control system of multiple stages of pulp preheaters in the high-pressure acid leaching and feeding process. On the basis of an existing liquid level control system of the multiple stages of pulp preheaters in the high-pressure acid leaching and feeding process, a feed pump for the multiple stages of pulp preheaters and a high-pressure kettle feed pump are each provided with a load distributor; a load primary datum setter with the output end connected with the input ends of both the load distributors at the same time is added; a flow control module is arranged for the multiple stages of pulp preheaters; meanwhile, the liquid level deviation of the preheaters is converted into a flow addition set value through a liquid level controller to be output. The flow set value is given through the load distributors according to the load primary datum set value given by the load primary datum setter, the rated load value of the feed pump and the load fine-adjusting coefficient and meanwhile overlapped by the flow addition set value, and the flow control module gives a feed pump flow adjusting instruction according to the flow deviation so that flow can be adjusted; by means of the load and liquid level coordinative control system, the adjustment continuity and stability of production loads and the stability of liquid levels of all stages of preheaters are ensured.

Description

technical field [0001] The invention belongs to the technical field of control, and in particular relates to a load-liquid level coordinated control system of a multi-stage pulp preheater in a high-pressure acid leaching feeding process. Background technique [0002] With the increasing depletion of nickel sulfide ore resources, efficient and low-cost treatment of laterite nickel ore is of great significance to meet the growing demand for nickel. In recent years, based on high pressure acid leaching (High Pressure Acid Leaching, HPAL) Laterite nickel ore hydrometallurgy technology has made great progress. [0003] In the high-pressure acid leaching process, the multi-stage pulp preheater is one of the key links. Its main function is to make the pulp reach the specified temperature through multi-stage preheating, and provide stable and qualified pulp for the subsequent high-pressure leaching process. material flow. The high-pressure acid leaching feeding process consists of...

AI Technical Summary

Problems solved by technology

For example: the adjustment of the load in actual production is first realized by changing the flow rate of the downstream autoclave feed pump. When the production is in a stable state and the load needs to be increased, the flow rate of the autoclave feed pump needs to be increased, which will lead to high temperature The discharge of the preheater increases accordingly, which causes the liquid level of the high temperature preheater to drop, such as figure 2 As shown, in order to maintain the stability of the liquid level of the high temperature preheater, the liquid level control system of the high temperature preheater needs to increase the feed of the high temperature preheater. Since the feed of the high temperature preheater increases, it is equivalent to the The discharge of the heater is also increased accordingly, so that the liquid level of the medium temperature preheater is reduced. At this time, the liquid level control system of the medium temperature preheater needs to increase the medium temperature preheating in order to maintain the stability of the liquid level in the medium temperature preheater. The feed to the low temperature preheater causes the liquid level of the low temperature preheater to drop, which eventually causes the liquid level control system of the low temperature preheater to increase the feed to the low temperature preheater

As mentioned above, it can be seen that the load adjustment starting point of the high-pressure acid leaching feeding process is at the feed pump of the downstream equipment autoclave. Under the action of the level control system, the feed volume of the preheaters at all levels is also continuously changing. The continuity of load adjustment can be ensured only by the transfer process of the liquid level fluctuations of the preheaters at all levels. However, due to the The volume of the preheater is limited, and the diameter of the preheater is relatively small relative to its height. If the preheater liquid level continues to fluctuate, it will easily exceed the allowable liquid level range. A low liquid level may cause the preheater to evacuate, and a high liquid level Spillage can cause the feed pump to reverse, both of which will damage the feed pump

In the actual production process, when the load is reduced, it is similar to the above-mentioned situation of increasing the load. The adjustment sequence of load reduction is still transmitted from the downstream equipment to the upstream equipment in reverse order, but the liquid level of each preheater is increased one by one. From the on-site process Parameter History Curve figure 2 It can be seen that the fluctuation of the liquid level of preheaters at all levels is relatively serious, and it is difficult to achieve the process requirements of stable liquid level of preheater with conventional liquid level control methods

[0004] The main reason why the liquid level of the preheaters at all levels fluctuates and becomes unstable in order to ensure the load stability is that the low temperature preheater, the medium temperature preheater, the high temperature preheater and the The autoclave is connected in series, which makes the material connection very close, but when designing the control system of the high-pressure acid leaching feeding process, the multi-stage preheater and the autoclave are not considered as a whole, but they are regarded as relatively independent equipment Separate control, that is: only the liquid level control system of preheaters at all levels, but lacks a unified load-liquid level coordinated control mechanism

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